Since the early seventies, I have been able to make my body go numb. The first times I fell because I didn't know what was coming. I have been able to do this at will for many years, but took care not to fall down. Fortunately, the feeling always returned.
As stubbornness is the nature of us on this site, I have only listened to Richard in the last six or so months when he admonished me not to do that! I can also dislocate my hip but he says not to do that either! (Takes all the fun out of life - no?) (No)
So - what IS the point - simply put: the ability is gone. I cannot do it anymore AT ALL. Not even a tingle and certainly no numbness. Yes, the quiet improvements continue - and the energy is very, very nearly back to my norm or 55 years. Keep at it - it pays.
Years later, one of my six MRIs picked up a lesion in my neck the only MRI to go down far enough, and caused many pieces of evidence to come together. One of those is, of course, that, at least in my opinion, PPMS is a flimsy label seized upon by frantic neuros looking for answers to our slippery presentations. I bet that most if not all PPMS patients can find other symptoms of much older disease whan they get their minds back and get tuned in - as this site can do.